Category Archives: Heart Disease

Low-Carb Diets Improve Cardiovascular Disease Risk Factors

This Shrimp Salad is truly low-carb

A meta-analysis by Chinese investigators found that low-carb diets improve cardiovascular risk factors. Specifically: body weight (lowered), triglycerides (lowered), HDL-cholesterol (raised), blood pressure (lowered systolic and diastolic, but less than 2 points).

Additionally, they found increases in total cholesterol  and HDL-cholesterol. Some consider those to be going in the wrong direction, increasing cardiovascular risk. The study authors, however, considered these increases “slight,” implying lack of real-world significance.

I’ll not fisk the entire research paper. Have a go at it yourself by clicking the link to full-text below.

The researchers included 12 randomized controlled trials in their analysis. They defined low-carb diets as having less than 40% of calories derived from carbohydrates. If you’re eating 2200 calories a day, 39% of calories from carb would be 215 g of carbs/day. That’s a lot of carb, and wouldn’t be much lower than average. I scanned the report pretty quickly and didn’t run across an overall average for carb grams or calories in the low-carb diets. The “control diets” had 45–55% of calories from carbohydrate.

Here’s the abstract:

Background

Low-carbohydrate diets are associated with cardiovascular risk factors; however, the results of different studies are inconsistent.

Purpose

The aim of this meta-analysis was to assess the relationship between low-carbohydrate diets and cardiovascular risk factors.

Method

Four electronic databases (PubMed, Embase, Medline, and the Cochrane Library) were searched from their inception to November 2018. We collected data from 12 randomized trials on low-carbohydrate diets including total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides, and blood pressure levels, as well as weight as the endpoints. The average difference (MD) was used as the index to measure the effect of a low-carbohydrate diet on cardiovascular risk factors with a fixed-effects model or random-effects model. The analysis was further stratified by factors that might affect the results of the intervention.

Results

From 1292 studies identified in the initial search results, 12 randomized studies were included in the final analysis, which showed that a low-carbohydrate diet was associated with a decrease in triglyceride levels of -0.15mmol/l (95% confidence interval -0.23 to -0.07). Low-carbohydrate diet interventions lasting less than 6 months were associated with a decrease of -0.23mmol/l (95% confidence interval -0.32 to -0.15), while those lasting 12–23 months were associated with a decrease of -0.17mmol/l (95% confidence interval -0.32 to -0.01). The change in the body weight in the observation groups was -1.58kg (95% confidence interval -1.58 to -0.75); with for less than 6 months of intervention, this change was -1.14 kg (95% confidence interval -1.65 to -0.63),and with for 6–11 months of intervention, this change was -1.73kg (95% confidence interval -2.7 to -0.76). The change in the systolic blood pressure of the observation group was -1.41mmHg (95% confidence interval—2.26 to -0.56); the change in diastolic blood pressure was -1.71mmHg (95% confidence interval—2.36 to -1.06); the change in plasma HDL-C levels was 0.1mmHg (95% confidence interval 0.08 to 0.12); and the change in serum total cholesterol was 0.13mmol/l (95% confidence interval 0.08 to 0.19). The plasma LDL-C level increased by 0.11mmol/l (95% confidence interval 0.02 to 0.19), and the fasting blood glucose level changed 0.03mmol/l (95% confidence interval -0.05 to 0.12),which was not significant.

Conclusions

This meta-analysis confirms that low-carbohydrate diets have a beneficial effect on cardiovascular risk factors but that the long-term effects on cardiovascular risk factors require further research.

Source: The effects of low-carbohydrate diets on cardiovascular risk factors: A meta-analysis

Steve Parker, M.D.

PS: The Paleobetic Diet provides roughly 60 grams/day of digestible carbohydrate.

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Is the Ornish diet really the most heart-healthy?

Pulmonary artery arrow is wrong

From Cardiovascular Business:

The Mediterranean diet has been eclipsed as the U.S. News & World Report’s best-ranked heart-healthy diet for the first time in a decade, nudged out of the top spot by the popular Ornish diet.

The Ornish diet—also ranked as the ninth-best overall diet in the 2020 report—was pioneered by physician Dean Ornish more than 40 years ago and restricts the consumption of fats, refined carbohydrates and animal proteins. It also emphasizes the importance of exercise and stress management in living healthfully.

Source: Ornish beats Mediterranean as best heart-healthy diet of 2020

I’ve always associated the Ornish diet with group therapy, meditation, and vegetarianism. But no mention of those in the linked article. I can’t remember the last time I met anybody doing the Ornish diet, it’s been that long. It was popular in the 1990s.

We don’t know how well he paleo diet ranks as a heart-healthy diet because it’s never been adequately tested as such.

Steve Parker, M.D.

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Tea May Postpone Death and Prevent Heart Disease

One of my favorite green teas

For years we’ve been hearing about the potential longevity and cardiovascular benefits of green tea. If memory serves, most of the data comes from Japanese studies. Now a Chinese observational study finds 15–20% reductions in atherosclerotic cardiovascular disease (ASCVD) and death, compared to non-tea drinkers. Most of the participants drank green tea, and they did so at least thrice weekly.

From the European Journal of Preventive Cardiology:

Using large prospective cohorts among general Chinese adults, we have provided novel evidence on the protective role of tea consumption on ASCVD events and all-cause mortality, especially among those who kept the habit all along. The current study indicates that tea might be a healthy beverage for primary prevention against ASCVD and premature death.

Source: Tea consumption and the risk of atherosclerotic cardiovascular disease and all-cause mortality: The China-PAR project – Xinyan Wang, Fangchao Liu, Jianxin Li, Xueli Yang, Jichun Chen, Jie Cao, Xigui Wu, Xiangfeng Lu, Jianfeng Huang, Ying Li, Liancheng Zhao, Chong Shen, Dongsheng Hu, Ling Yu, Xiaoqing Liu, Xianping Wu, Shouling Wu, Dongfeng Gu,

The researchers point out that results may not apply to non-Chinese populations.

Steve Parker, M.D.

h/t to Jan at The Low Carb Diabetic (click link for more details about the study)

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Diabetes Drug Dapagliflozin Reduced Cardiovascular Deaths and Worsening Heart Failure Even in Those Without Diabetes

 

Not dapagliflozin

The amazing thing about this research is that dapagliflozin 10 mg/day seemed to benefit patient who didn’t even have diabetes. Unfortunately, the abstract doesn’t mention how many non-diabetic patients were in the study.

Conclusion from the abstract:

Among patients with heart failure and a reduced [left ventricular] ejection fraction [under 40%], the risk of worsening heart failure or death from cardiovascular causes was lower among those who received dapagliflozin than among those who received placebo, regardless of the presence or absence of diabetes.

Source: Dapagliflozin in Patients with Heart Failure and Reduced Ejection Fraction | NEJM

Are Heart Artery Stenting and Bypass Really Necessary?

Pulmonary artery arrow is wrong

Doctors are often criticised for over-using coronary artery angioplasty/stenting and coronary artery bypass grafting.

From Stanford Medicine:

Patients with severe but stable heart disease who are treated with medications and lifestyle advice alone are no more at risk of a heart attack or death than those who undergo invasive surgical procedures, according to a large, federally-funded clinical trial led by researchers at the Stanford School of Medicine and New York University’s medical school.

The trial did show, however, that among patients with coronary artery disease who also had symptoms of angina — chest pain caused by restricted blood flow to the heart — treatment with invasive procedures, such as stents or bypass surgery, was more effective at relieving symptoms and improving quality of life.

“For patients with severe but stable heart disease who don’t want to undergo these invasive procedures, these results are very reassuring,” said David Maron, MD, clinical professor of medicine and director of preventive cardiology at the Stanford School of Medicine, and co-chair of the trial, called ISCHEMIA, for International Study of Comparative Health Effectiveness with Medical and Invasive Approaches.

***

“Based on our results, we recommend that all patients take medications proven to reduce risk of heart attack, be physically active, eat a healthy diet and quit smoking,” Maron said. “Patients without angina will not see an improvement, but those with angina of any severity will tend to have a greater, lasting improvement in quality of life if they have an invasive heart procedure. They should talk with their physicians to decide whether to undergo revascularization.”

Source: Stents, bypass surgery show no benefit in heart disease mortality rates among stable patients | News Center | Stanford Medicine

Steve Parker, M.D.

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Prevent Cardiovascular Events By Taking Hypertension Meds at Bedtime

High blood pressure is linked to heart attacksVery

This may be the most important biomedical research of 2019. Very recently I have noticed hypertension patients taking their medications at bedtime. Now I know why.

From Medscape:

Taking antihypertensive medication at bedtime led to an almost halving of cardiovascular events in a new study.

The Hygia Chronotherapy Trial is the largest ever study to investigate the effect of the time of day when people take their antihypertensive medication on the risk of cardiovascular events.

The trial randomly assigned 19,084 patients to take their medication on waking or at bedtime and followed them for an average of 6 years.Results showed that patients who took their pills at bedtime had a 45% reduction in overall cardiovascular events. This included a 56% reduction in cardiovascular death, a 34% reduction in myocardial infarction (MI), a 40% reduction in coronary revascularization [bypass surgery and angioplasty/stenting], a 42% reduction in heart failure, and a 49% reduction in stroke, all of which were statistically significant.

***

“We showed that if blood pressure is elevated during sleep then patients have increased cardiovascular risk regardless of daytime pressure, and if blood pressure during sleep is normal then cardiovascular risk is low even if the [doctor’s] office pressure is elevated,” Hermida said.

***

Results showed that during the 6.3-year median patient follow-up, 1752 participants experienced the primary cardiovascular disease (CVD) outcome (a composite of CVD death, MI, coronary revascularization, heart failure, or stroke).

Drug classes as physicians’ disposal were ARBs (angiotensin receptor blockers, calcium channel blockers, ACE inhibitors, and diuretics. Preventative effects were most pronounced for ARBs and ACE inhibitors.

Don’t change your BP medication dosing until you check with your personal physician.

Source: Bedtime Dosing of Hypertension Meds Reduces CV Events

Did you know most heart attacks occur in the morning, and those tend to be the most serious?

Steve Parker, M.D.

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Particular Diabetes Drugs May Protect Your Heart and Kidneys

 

Blood pressure control is also extremely important for protection of heart and kidneys

I’ve been reticent to tout the putative heart-protective effects of diabetes drugs in the classes called SGLT2 inhibitors and GLP-1 receptor agonists. Frankly, their supposed kidney-protective effects haven’t even been on my radar. My hesitation to report on these matters stems from:

Maybe if Big Pharma sent me a nice check….

The GLP-1 receptor agonists seem to have beneficial effects on both heart and kidney. With SGLT2 inhibitors, renal benefits may be more prominent than cardiac. Also note that any beneficial heart or renal effects may be attributable only to certain drug within the class, and not a class effect.

For what it’s worth, the American Diabetes Association recently hosted a conference on these issues. I assume the ADA endorses the report written by three experts, two of whom have received some sort of compensation from pharmaceutical companies. This doesn’t necessarily mean they are biased. Some excerpts:

Since patients with diabetes are at increased risk for CV [cardiovascular] and renal events, reducing the risk of these events is of primary interest to improve outcomes in the long-term. [Cardiovascular events usually refers to heart attacks, strokes, and death from those. Renal events would be high loss of protein through the kidneys, impaired kidney function or chronic kidney disease, or the need for dialysis.]

SGLT2 inhibitors and GLP-1 RAs have dramatically changed the treatment landscape of type 2 diabetes due to their established CV benefits, and the observed improvements in renal function seen with these classes of agents are currently undergoing intense investigation.

***

It is now apparent that both SGLT2 inhibitors and GLP-1 RAs show consistent reductions in major adverse cardiovascular events for patients with established cardiovascular (CV) disease, and both appear to have renal benefits as well.

***

The nephron is the microscopic structural and functional unit of the kidney.

Renal effects of GLP-1 receptor agonists

These drugs may exert their beneficial actions on the kidneys through their effects on lowering blood glucose and blood pressure and by reducing the levels of insulin.

For GLP-1RAs, these [studies] include ELIXA with lixisenatide, LEADER with liraglutide, SUSTAIN-6 with semaglutide, EXCSEL with exenatide once-weekly, HARMONY with albiglutide, and REWIND with dulaglutide.

All these studies indicate that albuminuria [protein loss through urine] is reduced during treatment with GLP-1 RAs, and eGFR [estimated glomerular filtration rate, a measure of kidney function] appears to be stabilized.

These benefits are seen independently of HbA1c, weight, and blood pressure variations.

***

Heart attack is only one type of cardiovascular event

Cardiovascular effects of GLP-1 receptor agonists

Large CV outcomes trials with GLP-1 RAs have shown that these agents can reduce the risk of major adverse CV events, CV mortality, and all-cause mortality.

These CV benefits appear to be related to four distinct mechanisms:

    • Improve myocardial [heart muscle] performance in ischemic heart failure [caused by poor blood flow to heart]
    • Improve myocardial survival in ischemic heart disease
    • Ameliorate endothelial dysfunction [endothelium is the lining of arteries]
    • Decrease markers of CV risk.

***

Renal effects of SGLT2 inhibitors

  • However, many potential mechanisms have been linked to the renoprotective effects of SGLT2 inhibitors.
  • These include reduction of blood pressure, improved metabolic parameters, reduced volume overload, reduction in albuminuria, and glomerular pressure.
  • For the latter, SGLT2 inhibition appears to reduce hyperfiltration via a tubuloglomerular feedback mechanism.
  • Clinical data from CV outcomes trials have shown consistent variations in eGFR and reduction in death from renal causes with empagliflozin, canagliflozin, and dapagliflozin.
  • However, to gain more information about the renal effects of these agents, dedicated renal outcomes trials are needed to study reductions in albuminuria, changes in eGFR, number of patients reaching end-stage renal disease, need for dialysis, and deaths due to kidney failure.

***

Key Messages from the authors

Large CV outcomes trials have shown that both SGLT2 inhibitors and GLP-1 RAs are associated with significant reductions in CV events in patients with elevated CV risk.

From CV outcomes trials both classes of agents also appear to have renal benefits, although large dedicated studies are needed to establish the magnitude of this potential benefit

The mechanism of action at the basis of CV and renal benefits of SGLT2 inhibitors and GLP-1 RAs is complex, multifactorial, and still not completely understood.

I’m still skeptical but will keep an open mind.

Steve Parker, M.D.

PS: Bold emphasis above is mine.

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Diet Quality Affects Risk of Cardiovascular Disease in Post-Menopausal Diabetic Women

Not your average cave-woman

Regarding the mention of paleo diet below, I rather doubt the study at hand hand significant numbers of paleo diet followers. From the Journal of the American Heart Association:

ABSTRACT

Background Dietary patterns are associated with cardiovascular disease (CVD) risk in the general population, but diet-CVD association in populations with diabetes mellitus is limited. Our objective was to examine the association between diet quality and CVD risk in a population with type 2 diabetes mellitus.

Methods and Results

We analyzed prospective data from 5809 women with prevalent type 2 diabetes mellitus at baseline from the Women’s Health Initiative. Diet quality was defined using alternate Mediterranean, Dietary Approach to Stop Hypertension, Paleolithic, and American Diabetes Association dietary pattern scores calculated from a validated food frequency questionnaire. Multivariable Cox’s proportional hazard regression was used to analyze the risk of incident CVD. During mean 12.4 years of follow-up, 1454 (25%) incident CVD cases were documented. Women with higher alternate Mediterranean, Dietary Approach to Stop Hypertension, and American Diabetes Association dietary pattern scores had a lower risk of CVD compared with women with lower scores (Q5 v Q1) (hazard ratio [HR]aMed 0.77, 95% CI 0.65-0.93; HRDASH 0.69, 95% CI 0.58-0.83; HRADA 0.71, 95% CI 0.59-0.86). No association was observed between the Paleolithic score and CVD risk.

Conclusions

Dietary patterns that emphasize higher intake of fruits, vegetables, whole grains, nuts/seeds, legumes, a high unsaturated:saturated fat ratio, and lower intake of red and processed meats, added sugars, and sodium are associated with lower CVD risk in postmenopausal women with type 2 diabetes mellitus.

Source: Diet Quality and Cardiovascular Disease Risk in Postmenopausal Women With Type 2 Diabetes Mellitus: The Women’s Health Initiative. – PubMed – NCBI

Steve Parker, M.D.

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Red Meat Not Quite as Deadly as Imagined

From New York Times:

Public health officials for years have urged Americans to limit consumption of red meat and processed meats because of concerns that these foods are linked to heart disease, cancer and other ills.

But on Monday, in a remarkable turnabout, an international collaboration of researchers produced a series of analyses concluding that the advice, a bedrock of almost all dietary guidelines, is not backed by good scientific evidence.

Whew…What a relief! Dodged that bullet.

Click for Gina Kolata’s article.

Steve Parker, M.D.

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Tighter Blood Pressure Control Benefits Folks With Diabetes

Not bad

For decades, physicians thought a blood pressure of under 140/90 was adequate for preventing heart attacks, strokes, and premature death. Not so.

From Diabetes Self-Management:

The new study evaluated roughly 11,000 people with type 2 diabetes in 20 countries over four years, finding that those who received the blood pressure drugs perindopril and indapamide to keep their blood pressure levels at or below 130/80 had fewer heart attacks, strokes and other complications than those receiving placebo (inactive treatment). They also had a “lower overall risk of dying from any cause.”

Source: Tight Blood Pressure Control Benefits Type 2 Diabetes: Study – Diabetes Self-Management

You may think the aforementioned health benefits stem from use of perindopril and/or indapamide. It’s either that, or simply the result of BP lowering. I suspect it’s the latter while admitting that not all BP drugs are created equal. As a hospitalist in Scottsdale, AZ, I rarely run across patients taking perindopril, and only occasionally folks on indapamide. The popularity of various drugs often depends on which part of the country you’re in and the attractiveness of the drug reps visiting the prescribers. We need to be more scientific than that.

Steve Parker, M.D.

PS: Losing excess weight and exercise are two ways to lower blood pressure without the expense and side effects of drugs.

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